JPH0827440A - Double-sided tacky tape - Google Patents

Abstract

PURPOSE:To obtain a double-sided tacky tape usable for applications under a load of a small stress for a long period even for an interior trim materials or parts using a hardly bondable polypropylene-based resin as a material and applications requiring the transparency without any fear of peeling or slippage. CONSTITUTION:This double-sided tacky tape has a tacky agent layer, formed out of a tacky agent composition containing an alkyl (meth)acrylate-based polymer having the number of carbon atoms in an alkyl group within the range of 2-15 and a tackifier resin having small compatibility with the polymer and toluene in an amount of at least >=50wt.% based on the whole and having 5-10% haze value. Furthermore, the double-sided tacky tape is prepared by laminating acrylic tacky agent layers consisting essentially of an alkyl (meth) acrylate-based polymer having the number of carbon atoms within the range of 2-15 onto both surfaces of a nonwoven fabric, made without using a binder' and containing >=35wt.% hemp as a substrate.

Description

Detailed Description of the Invention

The present invention relates to a double-sided adhesive tape.

[0002]

2. Description of the Related Art In recent years, a double-sided adhesive tape has been widely used for mounting interior materials for automobiles and parts for office automation equipment. Of these interior materials and parts, especially when used in applications where a small stress is applied for a long time in bonding with a material made of polypropylene resin, often,
The phenomenon of peeling and slippage has occurred, and there is a strong demand for improvement.

As an attempt to improve the above problems, for example, JP-A-64-16882 describes a double-sided pressure-sensitive adhesive tape using a pressure-sensitive adhesive containing a tackifying resin having poor compatibility with a polymer. However, the haze value of the pressure-sensitive adhesive layer is almost opaque as 15 to 95 as described in the publication, the appearance is whitish, and white is flickering from the side, and the overall color balance is lost. It is disliked for this reason, and it cannot be used especially for applications requiring transparency.

[0004]

SUMMARY OF THE INVENTION The present invention overcomes the above-mentioned drawbacks of the prior art. The object of the present invention is to provide interior materials and parts made of polypropylene resin, which is difficult to adhere to. An object of the present invention is to provide a double-sided pressure-sensitive adhesive tape that can be used in applications where a small stress is applied for a long period of time without fear of peeling or slippage and which is required to be transparent.

[0005]

The present invention according to claim 1 provides an adhesive having a low compatibility with a (meth) acrylic acid alkyl ester polymer in which the alkyl group has 2 to 15 carbon atoms. 5 with the applied resin and at least the whole
A double-sided pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing 0% by weight or more of toluene and having a haze value of 5 to 10% is a gist thereof.

The present invention according to claim 2 is based on a non-woven fabric which is produced without using a binder and contains hemp in an amount of 35% by weight or more.
The gist of the present invention is a double-sided pressure-sensitive adhesive tape obtained by laminating an acrylic pressure-sensitive adhesive layer containing a (meth) acrylic acid alkyl ester-based polymer in the range of 15 to 15 as a main component.

As the (meth) acrylic acid alkyl ester-based polymer used in the present invention according to claims 1 and 2, any one can be used as long as the alkyl group has 2 to 15 carbon atoms. However, for example,
Ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, octyl (meth) acrylate, (meth)
2-Ethylhexyl acrylate, (meth) acrylic acid alkyl ester such as decyl (meth) acrylate is used as a main component, and the above-mentioned (meth) acrylic acid alkyl ester is used alone or a monomer copolymerizable therewith. It is a polymer obtained by polymerization or copolymerization according to a conventional method in combination with, and has a weight average molecular weight of 20.
10,000 or more is preferable.

When the weight average molecular weight of the above (meth) acrylic acid alkyl ester polymer is less than 200,000, sufficient adhesive strength cannot be obtained. Further, any of those having an alkyl group having a carbon number outside the range of 2 to 15 has a high glass transition point, and thus the obtained polymer is not suitable for a pressure-sensitive adhesive.

The tackifying resin used in the present invention according to claims 1 and 2 has poor compatibility with the above-mentioned (meth) acrylic acid alkyl ester-based polymer. For example, pentaerythritol of disproportionated rosin is used. Examples thereof include esters (softening temperature 125 ° C.) and pentaerythritol esters of rosin (softening temperature 125 ° C.).

When the above-mentioned adhesive is used,
It is also preferable to crosslink using a crosslinking agent such as toluylene diisocyanate, naphthylene-1,5-diisocyanate, diphenylmethane diisocyanate.

In the double-sided pressure-sensitive adhesive tape according to the second aspect of the present invention, the binder is not used in the nonwoven fabric as the base material. Nonwoven fabrics generally used as a base material for double-sided adhesive tapes include polyvinyl alcohol, vinyl acetate resin emulsion, rubber latex, hot latex, depending on the type of natural fiber, pulp, synthetic fiber used, the use of the nonwoven fabric, the manufacturing method, etc. Binders such as melt adhesives are selectively used to give strength and other properties to the resulting non-woven fabric, but on the other hand, they cover the structure of the various fibers described above, so the spaces between the fibers are filled and the surface area is small. It has become.

In the double-sided pressure-sensitive adhesive tape according to the second aspect of the present invention, hemp fibers are used as the non-woven fabric as the base material, but it is sufficient that the hemp fibers contain 35% by weight or more of the constituent fibers of the non-woven fabric. The constituent fibers can be appropriately selected and used from rayon, pulp, and other synthetic fibers depending on the application.

When the composition ratio of hemp fibers in the above-mentioned non-woven fabric is less than 35% by weight, when the interior materials, measuring instruments and parts of automobiles are fixed with the double-sided adhesive tape, the double-sided adhesive tape fixing surface is When a so-called constant load, in which a small stress is applied for a long time, is applied, if peeling begins, it will be peeled off as it is, or a gap will occur.
It cannot exert a sufficient adhesive effect.

[0014]

The double-sided pressure-sensitive adhesive tape of the present invention according to claim 1 is a tackifying resin having a small compatibility with a (meth) acrylic acid alkyl ester-based polymer having an alkyl group in the range of 2 to 15 carbon atoms. And at least 50% by weight of the whole
A (meth) acrylic acid alkyl ester-based polymer having an alkyl group with 2 to 15 carbon atoms, which is formed from a pressure-sensitive adhesive composition containing the above toluene.
When the tackifying resin having a low compatibility with this swells and dissolves at least 50% by weight or more of the total amount of toluene, both are applied to the tape base material and dried to form a pressure-sensitive adhesive layer. The components forming the pressure-sensitive adhesive layer are melted together to form an extremely transparent pressure-sensitive adhesive layer having a haze value in the range of 5 to 10. Therefore, it shows an extremely large adhesive force, and in particular, when a so-called constant load in which a small stress is applied for a long time is applied, when it starts peeling, a slip stick phenomenon that is not acceleratedly peeled as it is, that is, When a peeling force is applied, if a little peeling occurs, a large stress is applied to the peeling traces so that the traces of the adhesive layer remain as horizontal stripes parallel to the peeling direction, and continuous peeling does not occur, excellent performance. To demonstrate.

Further, in the double-sided pressure-sensitive adhesive tape of the present invention as defined in claim 2, since no binder is used in the non-woven fabric as a base material, the double-sided pressure-sensitive adhesive tape has good compatibility with the pressure-sensitive adhesive layer, shows a strong anchor, and has a high elasticity. Since it contains 30% by weight or more of strong hemp, it is in an adhesive state exhibiting the above-mentioned slip stick phenomenon when a constant load is applied, so that it does not peel off from the adhered part or cause a shift. .

[0016]

EXAMPLES Examples of the present invention will be specifically described below, but the present invention is not limited thereto. In the embodiment of the invention according to claim 1, the haze value of the pressure-sensitive adhesive layer is 75 μm in thickness.
m Transparent polyester film (FE2, manufactured by Nimura Chemical Co., Ltd.)
000- # 75), the pressure-sensitive adhesive layer provided in a thickness of 50 μm was measured for total light transmittance and diffuse transmittance of this composite film, and was calculated by the following formula. Haze value (%) = [(diffuse transmittance) / (total light transmittance)] × 100 Further, as a measuring instrument, an automatic digital haze meter (NDH-20D) manufactured by Nippon Denshoku Industries Co., Ltd. was used.

The constant load peel test is a test method for evaluating the performance of the double-sided pressure-sensitive adhesive tape against a constant load when it is attached to a curved surface. For example, urethane foam is formed into a strip shape with a double-sided pressure-sensitive adhesive tape on a cylindrical surface. This method is suitable for evaluating the state in which the end faces of the urethane foam that have abutted against each other are flipped over to return to the original flat sheet shape when they are attached one round. First, as shown in FIG. 1, a double-sided adhesive tape 2 to be tested having a width of 20 mm was attached on one side to the back side of a polypropylene plate 1 having a thickness of 5 mm, and the other side was protected by a polyester film 3 having a thickness of 75 μm. After that, in the embodiment of the invention described in claim 1, in the embodiment of the invention described in claim 1, a laminating roller of 5 kg is reciprocated once and pressure-bonded, and the double-sided adhesive tape 2 to be tested and the polypropylene plate 1 are tested. Stick it tightly so that there are no air bubbles between them. Then, in a test room kept at 60 ° C., a grip 4 is applied to one end 21 of the double-sided adhesive tape that has been pasted so as to be evenly loaded in a width of 20 mm, and a load 5 of 80 g is applied thereto.
This state was maintained for 3 hours, after which the peeled length L was measured.

(Example 1 = Invention according to claim 1) n-butyl acrylate 80 parts by weight, 2-ethylhexyl acrylate 17 parts by weight, acrylic acid 3 parts by weight, acrylic acid 2-
0.10 parts by weight of hydroxyethyl was subjected to boiling point polymerization with 50% by weight of ethyl acetate to obtain a polymer having a weight average molecular weight of 500,000.

A solution of the obtained polymer in ethyl acetate was diluted with toluene so that the proportion of toluene in the total solution was 50% by weight, and 2 parts by weight of the crosslinking agent 2,4-toluylene diisocyanate was added. A sample for haze value measurement was prepared by uniformly stirring and coating on a polyester film having a thickness of 75 μm with a roll coater. Then, without using a binder, a roll coater was used to form a pressure-sensitive adhesive layer of 65 μm on each side of a nonwoven fabric having a basis weight of 14 g / m ² consisting of 35 parts by weight of hemp, 20 parts by weight of rayon, and 45 parts by weight of pulp. Then, a double-sided adhesive tape was manufactured. The haze value and the constant load peeling test result are shown in Table 1.

Example 2 = Invention of Claim 1 n-butyl acrylate 48 parts by weight, 2-ethylhexyl acrylate 48 parts by weight, acrylic acid 4 parts by weight, acrylic acid 2-
0.10 part by weight of hydroxyethyl was subjected to boiling point polymerization using ethyl acetate as a solvent to obtain a polymer having a weight average molecular weight of 500,000.

A solution of the obtained polymer in ethyl acetate was diluted with toluene so that the proportion of toluene in the total solution was 55% by weight, and 2 parts by weight of the crosslinking agent 2,4-toluylene diisocyanate was added. After stirring uniformly, a sample for haze value measurement was prepared in the same manner as in Example 1. Then, in the same manner as in Example 1, a double-sided pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer of 65 μm was manufactured. The haze value and the constant load peeling test result are shown in Table 1.

(Comparative Example 1 = Comparison with the invention described in claim 1) The ethyl acetate solution of the polymer obtained in Example 1 was diluted with toluene so that the proportion of toluene in the total solution was 20.
A sample for measuring haze value was prepared in the same manner as in Example 1 except that the sample was prepared so as to have a weight percentage. Then, in the same manner as in Example 1, a double-sided pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer of 65 μm was manufactured. The haze value and the constant load peeling test result are shown in Table 1.

(Comparative Example 2 = Comparison with the invention described in claim 1) The ethyl acetate solution of the polymer obtained in Example 2 was diluted with toluene so that the proportion of toluene in the total solvent was 40.
A sample for measuring haze value was prepared in the same manner as in Example 1 except that the sample was prepared so as to have a weight percentage. Then, in the same manner as in Example 1, a double-sided pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer of 65 μm was manufactured. The haze value and the constant load peeling test result are shown in Table 1.

[0024]

[Table 1]

(Example 3 = Invention according to claim 2) A non-woven fabric having a basis weight of 14 g / m ^{2 which} is composed of 35 parts by weight of hemp, 20 parts by weight of rayon and 45 parts by weight of pulp without using a binder is used. , Acrylic adhesive (manufactured by Soken Chemical Industry Co., Ltd., trade name: SK Dyne 1717, solid content 45%, toluene 50
%) Was applied and dried to provide a pressure-sensitive adhesive layer with a thickness of 65 μm to manufacture a double-sided pressure-sensitive adhesive tape. The results of the constant load peel test are shown in Table 2.

(Example 4 = Invention according to claim 2) Both sides of a non-woven fabric having a basis weight of 14 g / m ^{2 which} is composed of 44 parts by weight of hemp, 6 parts by weight of rayon and 50 parts by weight of pulp without using a binder. The double-sided pressure-sensitive adhesive tape was manufactured by providing the pressure-sensitive adhesive layer described in Example 3 with a thickness of 65 μm. The results of the constant load peel test are shown in Table 2.

(Example 5 = Invention according to claim 2) A binder was not used, and Example 3 was used on both sides of a non-woven fabric consisting of 95 parts by weight of hemp and 5 parts by weight of rayon and having a basis weight of 14 g / m ^2.
A double-sided pressure-sensitive adhesive tape was manufactured by providing the described pressure-sensitive adhesive layer with a thickness of 65 μm. The results of the constant load peel test are shown in Table 2.

(Comparative Example 3 = Comparison with the invention of claim 2) 3 parts by weight of polyvinyl alcohol was used as a binder, 45 parts by weight of rayon, 50 parts by weight of pulp and 5 parts of hemp.
A double-sided pressure-sensitive adhesive tape was manufactured by providing the pressure-sensitive adhesive layer described in Example 3 with a thickness of 65 μm on both sides of a non-woven fabric having a basis weight of 14 g / m ² consisting of parts by weight. The results of the constant load peel test are shown in Table 2.

(Comparative Example 4 = Comparison with the invention of claim 2) 3 parts by weight of polyvinyl alcohol was used as a binder, 20 parts by weight of rayon, 45 parts by weight of pulp and 3 parts of hemp.
A double-sided pressure-sensitive adhesive tape was manufactured by providing a pressure-sensitive adhesive layer described in Example 3 with a thickness of 65 μm on both sides of a nonwoven fabric having a basis weight of 14 g / m ² consisting of 5 parts by weight. The results of the constant load peel test are shown in Table 2.

(Comparative Example 5 = Comparison with the invention according to claim 2) 3 parts by weight of polyvinyl alcohol was used as a binder, and 25 parts by weight of rayon, 45 parts by weight of pulp and 3 parts of hemp were used.
A double-sided pressure-sensitive adhesive tape was manufactured by providing the pressure-sensitive adhesive layer described in Example 3 with a thickness of 65 μm on both surfaces of a nonwoven fabric having a basis weight of 14 g / m ² consisting of 0 parts by weight. The results of the constant load peel test are shown in Table 2.

[0031]

[Table 2]

[0032]

According to the pressure-sensitive adhesive layer of the present invention as set forth in claim 1, since the respective components forming the pressure-sensitive adhesive layer are melted,
Slip stick phenomenon that shows extremely large adhesive force, and in particular, when a so-called constant load, in which a small stress is applied for a long time, is applied, it will not be peeled off acceleratedly as it is, that is, peeling force When a small amount is peeled off, a large stress is applied to the peeling trace so that the trace of the adhesive layer remains as horizontal stripes parallel to the peeling direction and continuous peeling does not occur, exhibiting excellent performance To do.

In the double-sided pressure-sensitive adhesive tape of the present invention according to claim 2, since no binder is used in the non-woven fabric as the base material, it is well compatible with the pressure-sensitive adhesive layer, exhibits a strong anchor, and has a low elasticity. Since it contains 30% by weight or more of strong hemp, it is in an adhesive state exhibiting the above-mentioned slip stick phenomenon when a constant load is applied, so that it does not peel off from the adhered part or cause a shift. .

[0034]

[Brief description of drawings]

FIG. 1 is an explanatory view for explaining a main part of a constant load peeling test method showing the performance of the double-sided pressure-sensitive adhesive tape of the present invention.

[0001]

[Explanation of symbols]

 1 Polypropylene plate 2 Double-sided adhesive tape 21 Edge of double-sided adhesive tape 3 Polyester film 4 Grip 5 Load

Claims (2)

[Claims] 1. A (meth) acrylic acid alkyl ester-based polymer having an alkyl group in the range of 2 to 15 carbon atoms, a tackifier resin having a low compatibility with the polymer, and at least 50% by weight or more of the total amount of toluene. A double-sided pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer having a haze value of 5 to 10%, which is formed from a pressure-sensitive adhesive composition containing 2. A non-woven fabric which is produced without using a binder and contains hemp in an amount of 35% by weight or more as a base material, and the carbon number of the alkyl group is in the range of 2 to 15 on both surfaces thereof (meta). ) A double-sided pressure-sensitive adhesive tape obtained by laminating an acrylic pressure-sensitive adhesive layer containing an acrylic acid alkyl ester-based polymer as a main component.